1. Field of the invention
The present invention relates to a light-emitting module and a lamp device for vehicles including the same.
2. Description of the Related Art
In general, vehicles are equipped with lamp devices for illuminating nearby objects during poor lighting conditions or signaling the state of driving to nearby vehicles or pedestrians.
The lamp device for a vehicle includes a head lamp mounted to the front side of the vehicle and a tail lamp mounted to the rear side of the vehicle. The head lamp is a lamp for illuminating the area ahead while driving at night. The tail lamp includes a brake lamp, which is turned on when a driver steps on a brake, and a turn signal lamp, which indicates the direction of travel of the vehicle.
Recently, light-emitting diodes or laser diodes have been used as light sources for automotive lamp devices for good energy efficiency.
In particular, laser diodes are receiving attention due to their high degree of straightness, long-distance illumination and non-disturbance of the field of vision of drivers of oncoming vehicles.
The laser diode needs a phosphor and a lens assembly in order to output white light. However, this complicates the structure of the automotive lamp device, reduces efficiency, and increases the volume of the device. The lamp device for vehicles having a conventional laser diode will now be described.
FIG. 19 is a conceptual view of a conventional light-emitting module. Referring to FIG. 19, a conventional light-emitting module operates in such a manner that blue light generated from a laser diode is focused while passing through a prism 3 and a lens 4, the focused light is reflected from a first reflection unit 5, passes through a light transmissive phosphor 6 and is converted into white light, and the white light is radiated forward from a second reflection unit 7.
However, if the light-emitting module is arranged lengthwise along an optical axis inside the head lamp for vehicles, the length of the head lamp may be increased.
Further, since the conventional light-emitting module needs a relatively large number of components and has an optical path structure in which the light passes through each component only once, it may be hard to manufacture a compact head lamp due to the overall size of the components.
In addition, using a large number of components may increase costs and deteriorate reliability, and using the light transmissive phosphor may cause a decrease in efficiency.